import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int flag1=0,flag2=0;
        int n = in.nextInt();
        int[] x=new int[n];
        int[] y=new int[n];
        for(int a0 = 0; a0 < n; a0++){
            x[a0] = in.nextInt();
            y[a0] = in.nextInt();
        }
        for(int i=0;i<(n-1);i++)
            {
            if(x[i]!=x[i+1])
                flag1=1;
            if(y[i]!=y[i+1])
                flag2=1;
        }
        if(flag1==0 || flag2==0)
            System.out.println("YES");
        else
            System.out.println("NO");
    }
}